Especially now that the Zika virus has officially arrived in the United States (via Florida), pregnant women across the country are worried about the possible effects that contracting this mosquito-born virus might have on their unborn children. Many health organizations like the Center for Disease Control (CDC) have concluded that the Zika virus is responsible for microcephaly (a condition where a baby is born with a smaller than normal head and can have long-term cognitive problems because of it). However, a new study raises some questions about these conclusions.

The New Study: does Zika Really Cause Microcephaly?

This new study was undertaken by the New England Complex Systems Institute (NECSI) and recently published in the prestigious New England Journal of Medicine. In it, researchers did a large study of 12,000 pregnant Columbian women who showed signs and symptoms of the Zika virus. What is interesting about this study, though, it that noneofthese12,000womengavebirthtobabieswithmicrocephaly.

At this time, there were four cases of microcephaly reported, but this would considered to be at the normal rate of this birth defect, which occurs in approximately 2 out of every 10,000 births even in unaffected populations.

The researchers estimate that, throughout Columbia, there are or have been around 60,000 pregnancies affected by the Zika virus, so the absence of microcephaly births raised the inevitable question: if the Zika virus is not causes microcephaly, then what is?

A New Culprit is Named

So if the Zika virus is not causing these birth defects, what is?

The NECSI believes that the real culprit might well be a pesticide called pyriproxyfen, which, ironically, is widely used in Brazil to help control the mosquito population. The chemical is used in areas which have been particularly affected by microcephaly — and it has been used in the public water supplies at unprecedented levels.

The researchers, in making their argument, pointed out the following facts:

Pyriproxyfen works to control the mosquito population by interfering with the development of larvae — and might well interfere with the development of human babies.

Its chemical structure is similar to a form of vitamin A known as a retinoid. The use of retinoids with women during pregnancy has been linked with a variety of serious birth defects, including microcephaly.

Pyriproxyfen has been used in Brazil in the public water supply at unprecedented levels — and this usage happened just before the outbreak of microcephaly in this country.

The fact that other countries who have suffered from Zika virus outbreaks have not suffered from large numbers of microcephaly is suspicious.

The Study in Context

This study should be looked at in context in order to really appreciate its importance. To begin with, the manufacturer of pyriproxyfen has denied any link between its pesticide and birth defects. However, this has been belied by a neurodevelopmental psychologist from the Harvard School of Public Health whose research found a link between this chemical and smaller skull size in laboratory animals.

In the meantime, the use of this pesticide remains widespread in Brazil despite worries that it might be causing these defects in unborn children. The good news is that some countries are exploring alternatives to mosquito control, that does not harm the human population in any way. This includes the use of larvae-eating fish and mosquito traps.

The long and short of it is that the Zika virus, while certainly a threat to public health, may not be the culprit behind the outbreak of microcephaly — and alternatives to the use of pyriproxyfen should be investigated in order to reduce the potential health risk to pregnant women and their developing babies.